A data processing system having a first processor, a second processor, a local memory of the second processor, and a built-in self-test (BIST) controller of the second processor which performs BIST memory accesses on the local memory of the second processor and which includes a random value generator is provided. The system can perform a method including executing a secure code sequence by the first processor and performing, by the BIST controller of the second processor, BIST memory accesses to the local memory of the second processor in response to the random value generator. Performing the BIST memory accesses is performed concurrently with executing the secure code sequence.